Pattern to avoid nested try catch blocks?

Question

Consider a situation where I have three (or more) ways of performing a calculation, each of which can fail with an exception. In order to attempt each calculation until we f

Answer 1

Given that the calculation methods have the same parameterless signature, you can register them in a list, and iterate through that list and execute the methods. Probably it would be even better for you to use Func meaning "a function that returns a result of type double".

using System;
using System.Collections.Generic;

namespace ConsoleApplication1
{
  class CalculationException : Exception { }
  class Program
  {
    static double Calc1() { throw new CalculationException(); }
    static double Calc2() { throw new CalculationException(); }
    static double Calc3() { return 42.0; }

    static void Main(string[] args)
    {
      var methods = new List> {
        new Func(Calc1),
        new Func(Calc2),
        new Func(Calc3)
    };

    double? result = null;
    foreach (var method in methods)
    {
      try {
        result = method();
        break;
      }
      catch (CalculationException ex) {
        // handle exception
      }
     }
     Console.WriteLine(result.Value);
   }
}